1. Field of the Invention
The invention relates to a thin film magnetic head comprising at least an inductive-type magnetoresistive transducer for writing and a method of manufacturing the same.
2. Description of the Related Art
In recent years, performance improvement in thin film magnetic heads has been sought in accordance with an increase in surface recording density of a hard disk drive. As a thin film magnetic head, a composite thin film magnetic head has been widely used. A composite thin film magnetic head has a layered structure which includes a recording head with an inductive-type transducer for writing and a reproducing head with a magnetoresistive device (also referred to as MR device in the followings) for reading-out. There are a few types of MR devices: one is an AMR device that utilizes the anisotropic magnetoresistance effect (referred to as AMR effect in the followings) and the other is a GMR device that utilizes the giant magnetoresistance effect (referred to as GMR effect in the followings). A reproducing head using an AMR device is called an AMR head or simply an MR head. A reproducing head using the GMR device is called a GMR head. The AMR head is used as a reproducing head whose surface recording density is more than 1 gigabit per square inch. The GMR head is used as a reproducing head whose surface recording density is more than 3 gigabit per square inch.
An AMR head includes an AMR film having the AMR effect. The GMR head has the similar configuration to the AMR head except that the AMR film is replaced with a GMR film having the GMR effect. However, compared to the AMR film, the GMR film exhibits a greater change in resistance under a specific external magnetic field. Accordingly, the reproducing output of the GMR head becomes about three to five times greater than that of the AMR head.
In order to improve the performance of a reproducing head, the MR film may be changed from an AMR film to a GMR film or the like which is made of a material with more excellent magnetoresistive sensitivity, or the pattern width of the MR film. Specifically the MR height may be adjusted appropriate. The MR height is the length (height) between the end of an MR device closer to an air bearing surface and the other end, and is determined by an amount of grinding when the air bearing surface is processed. The air bearing surface (ABS) is a surface of a thin film magnetic head facing a magnetic recording medium and is also called a track surface.
Performance improvement in a recording head has also been expected in accordance with the performance improvement in a reproducing head. The main factor which determines the performance of a recording head is the throat height (TH). The throat height is the length (height) of a portion of a magnetic pole from the air bearing surface to an edge of an insulating layer which electrically isolates the thin film coil. It is necessary to optimize the throat height in order to improve the performance of a recording head. The throat height is also controlled by an amount of grinding when the air bearing surface is processed.
It is necessary to increase the track density of a magnetic recording medium in order to increase the recording density among the performance of a recording head. In order to achieve this, a recording head with a narrow track structure in which the width of a bottom pole and a top pole sandwiching a write gap on the air bearing surface is required to be reduced to the order of some microns to submicron. Semiconductor process technique is used to achieve the narrow track structure.
A composite thin film magnetic head comprising a recording head and a reproducing head described above can be manufactured through a plurality of manufacturing steps such as sputtering, photolithography, electro-plating, etching, polishing and the like.
It is a problem that it requires a long lead-time to manufacture a thin film magnetic head through a series of manufacturing process including a various kinds of steps as described above. Specific improvement of methods such as reducing the number of steps is necessary in order to further shorten the lead-time in a case of mass production.
The invention has been designed to overcome the foregoing problems. An object of the invention is to provide a thin film magnetic head which has a high performance without complicating the manufacturing steps and a method of manufacturing the same.
A method of manufacturing a thin film magnetic head of the invention includes: two magnetic layers magnetically coupled to each other having two magnetic poles which face each other with a gap layer in between and are to be faced with a recording medium, a thin film coil provided between the two magnetic layers, and an insulating layer for insulating the thin film coil the two magnetic layers. One of the two magnetic layers includes: a first magnetic layer having a portion with a uniform width which defines a track width on the recording medium and a second magnetic layer which partially covers a region where the thin film coil is provided and partially overlaps to be magnetically coupled to the first magnetic layer. The method includes: a first step of forming a first thin film coil pattern and a first connection pattern in the end of the first thin film coil pattern so that the first thin film coil pattern and the first connection pattern are integrated into one body and constitute part of the thin film coil; a second step of forming the first magnetic layer and a second connection pattern, so that the first magnetic layer extends from a recording-medium-facing surface to be faced with the recording medium in a longitudinal direction and that the second connection pattern is located on the first connection pattern and constitutes part of the thin film coil; a third step of forming an insulating film as part of the insulating layer so as to cover at least the first thin film coil pattern, the first and second connection patterns, and the first magnetic layer; a fourth step of planarizing a surface of the insulating film by polishing until at least both the first magnetic layer and the second connection pattern are exposed; and a fifth step of forming a conductive layer pattern so as to be electrically connected to an exposed portion of the second connection pattern.
In a method of manufacturing a thin film magnetic head of the invention, a second connection pattern is provided on a first connection pattern provided in the end of a first thin film coil pattern through the same manufacturing step as that of a first magnetic layer. As a result, the level of the top surface of the second connection pattern is higher than that of the top surface of the first magnetic layer. Therefore, the second connection pattern is also exposed by polishing the surface of the insulating layer until the first magnetic layer is exposed after an insulating layer is formed. As the second connection pattern is formed through the same step as that of the first magnetic layer, it is not necessary to have another step of forming the second connection pattern.
A thin film magnetic head of the invention includes: two magnetic layers magnetically coupled to each other and having two magnetic poles which face each other with a gap layer in between and are to be faced with a recording medium, a thin film coil provided between the two magnetic layers, and an insulating layer for insulating the thin film coil from the two magnetic layers. One of the two magnetic layers includes: a first magnetic layer having a portion with a uniform width which defines a track width on the recording medium and a second magnetic layer which partially covers a region where the thin film coil is provided and partially overlaps to be magnetically coupled to the first magnetic layer. The thin film coil includes: a first thin film coil pattern; a first connection pattern provided in the end of the first thin film coil pattern so as to be integrated into one body with the first thin film pattern; and a second connection pattern formed on the first connection pattern, by using the same material as that of the first magnetic layer through the same step as that of forming the first magnetic layer. Also a conductive layer pattern is provided on the second connection pattern.
In a thin film magnetic head of the invention, the first connection pattern and a conductive layer are electrically connected through the second connection pattern provided therein. Thereby the first thin film coil pattern which is integrated into one body with the first connection pattern is electrically connected to the conductive layer.
In a method of manufacturing a thin film magnetic head of the invention, the first magnetic layer may be formed after the first thin film coil pattern is covered with the first insulating layer.
In a thin film head of the invention or a method of manufacturing the same, the insulating layer may be formed to include: a first insulating layer defining a forefront end of the insulating layer, the forefront end being located on the recording-medium-facing surface side; and a second insulating layer filling a space over the first insulating layer to the same level as the top of the first magnetic layer. It is preferable that the first insulating layer is formed of an organic insulating material and the second insulating layer is formed of an inorganic insulating material.
In a thin film magnetic head of the invention, it is preferable that the length from the forefront end of the first insulating layer to the forefront end portion of the first thin film coil pattern is equal to or more than the thickness of the first thin film coil pattern.
In a thin film magnetic head of the invention or a method of manufacturing the same, the conductive layer pattern may be formed as a wiring pattern for providing the first thin film coil pattern with a current. In such a case, it is preferable that the conductive layer pattern is formed of the same material as that of the second magnetic layer through the same step as that of forming the second magnetic layer.
In a method of manufacturing a thin film magnetic head of the invention, a fifth step may include a step of: forming a second thin film coil pattern on the planarized surface of the insulating film, the second thin film constituting part of the thin film coil and the conductive layer pattern is formed as a third connection pattern in the end of the second thin film coil pattern at the time of forming the second thin film coil pattern so as to be integrated into one body with the second thin film coil pattern. In such a case, a sixth step of forming a third insulating layer as part of the insulating layer so as to cover the second thin film coil pattern and the conductive layer pattern may be included.
In a thin film magnetic head of the invention, the thin film coil further includes a second thin film coil pattern provided between the first thin film pattern and the one of the tow magnetic layers with part of the insulating layer in between. In such a case, the conductive layer pattern may be formed as a third connection pattern which is integrated into one body with the second thin film coil pattern and is provided in the end of the second thin film coil pattern. The insulating layer further includes a third insulating layer which covers the second thin film coil pattern and the conductive layer pattern.
In a thin film magnetic head of the invention or a method of manufacturing the same, it is preferable that the third insulating layer is formed of an organic insulating material.
In a thin film magnetic head of the invention, it is preferable that the surface of the first insulating layer on the recording-medium-facing surface side is a given slope towards the surface of the gap layer and the average angle of the slope lies within the range of 5xc2x0 and 45xc2x0.
Other and further objects, features and advantages of the invention will appear more fully from the following description.